Film rewinding mechanism for cameras

ABSTRACT

A film rewinding mechanism for underwater cameras comprises a rewinding shaft adapted to engage film rewind gearing for film rewinding and to disengage from the gearing during film advancement. The shaft is provided with two coaxial gears having areas formed without teeth. During film advancement, the areas without teeth are in alignment to disengage the shaft from the rewind gearing; and during rewinding, the areas without teeth are out of alignment to form a continuous toothed gear in engagement with the rewind gearing.

United States Patent Shimizu May 9, 1972 [54] FILM REWINDING MECHANISMFOR [56] RelerencesClted C AMERAS FOREIGN PATENTS 0R APPLICATIONS [72]Inventor: Tenahlgg Shimhu, Tokyo, Japan 237,441 8/ i925 Great Britain..74/435 [73] Amati: Nippon Japan Pn'mary .ram|'ner-Samuel S. Matthews[221 Filed: Mar. 17, 1970 Assistant Examiner-Russell E. Adams, Jr.

s s 1 pp 20,327 Attorne) ard McElhannon Brooks& Fitzpatrick [57]ABSTRACT [30] F Applmuon A film rewinding mechanism for underwatercameras com Mar. 27, 1969 Japan ..44l26698 prises a rewinding shafladapted to engage film rewind gearing for film rewinding and todisengage from the gearing during [52] U.S.Cl ..242/7l.6,74/405,74l435.film advancement. The shaft is provided with two coaxial 95/l l UW.95/3| R gears having areas formed without teeth. During film advance-[Sl] III. Cl. ..G03p meat. the was without teeth a e in alignment todisengage 1 Md sunk "242/7115; 95/ 1 the shaft from the rewind gearing;and during rewinding, the

areas without teeth are out of alignment to form a continuous toothedgear in engagement with the rewind gearing.

5 Claims, 4 Drawing Figures PATENTEDMY 9 m2 -.-7 n I I IZI FILMREWINDING MECHANISM FOR CAMERAS BACKGROUND OF THE INVENTION The presentinvention relates generally to a camera and more particularly a filmrewinding mechanism for underwater cameras.

An O-ring is generally used as a sealing member over a rewinding shaftof an underwater camera so that the film winding operation requires muchforce because of the friction between the O-ring and the rewindingshalt. In order to eliminate this disadvantage, there has been proposeda clutch mechanism by which the film can be rewound by lifting therewinding knob and rotating it, but this mechanism is complicated inoperation because of the clutch operation-and its operation beingdifferent from the ordinary camera,operational errors tend to occur.

SUMMARY OF THE INVENTION In view of the above, the object of the presentinvention is to provide a film rewinding mechanism in which operationalcomplexity and errors are avoided because the rewinding mechanism can beoperated in the same manner as the ordinary camera, and the excess forcenecessary for winding the film which is caused by the friction betweenan O-ring and a rewinding shaft in the operation of film winding iseliminated.

In brief, the present invention provides an improved film rewindingmechanism for cameras in which a first gear which is adapted to rotatein unison with a rewinding knob and has a disengaging portion, Le. aportion formed without teeth, is rotatably disposed in coaxial relationwith a second gear having also a disengaging or no tooth portion, one ofthe gears being provided with a pin while the other gear is providedwith a slot in such a manner that the pin is fitted into said slot, bothof said gears being meshed with an intermediate gear which isoperatively coupled to a shaft which rotates a shaft of a filmcartridge, when the film is rewound, the pin and slot cooperating sothat both of the gears may constitute one complete gear having nodisengaging or no tooth portion whereby the continuous rotation of therewinding knob alone can be transmitted to the intermediate gear; andwhen the film is advanced or wound, the disengaging or no tooth portionsof said gears come to the position where said gears are to be meshedwith (or not be be meshed with) the intermediate gear, so that therotation cannot be transmitted to the rewinding knob.

The film rewinding mechanism in accordance with the present inventioneliminates the excessive force required to overcome the frictional forceproduced between an O-ring and a rewinding shaft in the conventionalmechanism. The film rewinding mechanism can be operated in the samemanner as the ordinary camera so that error of operation can bepositively prevented. The film rewinding mechanism can also ensuresmooth film rewinding operation.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description ofone illustrative embodiment thereof taken in conjunction with theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a sectional view of oneembodiment of the present invention;

FIG. 2 is a perspective view thereof;

FIG. 3 is a plan view illustrating the gear portion thereof and therelative positions of gears when the film is advanced or wound; and

FIG. 4 is a view similar to FIG. 3 but illustrating their positions whenthe film is rewound.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2,reference numeral 1 designates a rewind crank knob; 2, a rewind crank;3, a rewind knob; and 4, a gear which is made integral with a shaftwhich is screwed in the rewind knob 3, and provided with a disengagingportion 4a which is an arcuate portion of the gear 4 having no teeth. Apin 5 extending from the gear 4 is fitted into an arcuate slot 7b formedin agar 7 which is rotatably disposed on the shaft of the gear 4 andcoaxial therewith and has a disengaging portion 7a which is a portion ofthe gear 7 having no tooth as in the case of the gear 4. The pitch andpitch circle of the tooth of the gear 4 is the same as the gear 7. An0ring 6 is interposed and seals between the shaft of the gear 4 and anupper part of a camera body to be described hereinafter. An intermediategear 8 is journalled by a U-shaped member 9 which is carried by a shaftof a rewinding gear 10. The intermediate gear 8 is in mesh with thegears 4 and 7 so as to rotate the rewinding gear 10. A bearing 11 forthe rewinding gear 10 is fixed to a plate member I8. The rewinding gear10 is made in unitary construction with a rewinding gear shaft 12 whichis connectable with a film spool (not shown) and is journalled by thebearing 1 l. The U-shaped member 9 is normally biased by means of aspring I3 so as to rotate in the counterclockwise direction.

Next referring to FIGS. 3 and 4, a pin 14 serves to adjust the stopposition of the U-shaped member 9 and a pin I5 is so positioned as toprovide a small spacing between the pin 15 and the U-shaped member 9.Both of the pins 14 and 15 are fixed to the plate member I8. The freeend of the spring 13 is stopped by a pin 16 extending from the platemember I8.

Referring back to FIG. 1, the plate member 18 is fixed to the upper partof the camera body 17 by means of a setscrew 19 Next, the mode ofoperation will be described hereinafter. When the film is advanced, therewinding gear shaft 12 is caused to rotate in the direction indicatedby the arrow in FIG. 3 by the rotation of a film spool so that the gears4 and 7 are rotated through the intermediate gear 8. When thedisengaging portions 40 and 7a of the gears 4 and 7 come to the positionwhere said gears are not to be meshed with the intermediate gear 8, norotation is transmitted to the knob 3 through the gears 4 and 7 and onlythe rewinding gear 10 and this intermediate gear 8 are rotated.Therefore, the film advancement operation is disconnected from therewinding knob shaft.

To rewind the film, the rewinding knob 3 is rotated through therewinding crank knob l and the rewinding crank 2 so that the gear 4 isrotated in the direction indicated by the arrow in FIG. 4 while the gear7 remains stationary. When the disengaging portion 40 rotates past theintermediate gear 8, the teeth of the gear 4 engage with intermediategear 8 so that the rotation of gear 4 is transmitted to the rewindinggear 10 whereby the film is rewound. Then the pin 5 engages with the endof the arcuate slot 7b of the gear 7 so that, the latter is also causedto rotate and engage with the intermediate gear 8. The disengagingportion 4a of the gear 4 and the disengaging portion 74 of the gear 7are stopped by the pin 5 in such a relative position that thedisengaging portions are not superposed. This means that, in effect, onegear having teeth formed around the whole periphery thereof is formed bythe pair of gears 4 and 7 so that the rotation can be always transmittedto the rewinding gear 10 whereby film rewinding can be efi'ectedsmoothly. The film rewinding operation of the device of the presentinvention is not different from that of the conventional camera.

The present invention has been so far described with particularreference to one illustrative embodiment thereof, but it will beunderstood that variations and modifications can be effected withoutdeparting from the true spirit of the present invention as describedhereinabove and as defined in the appended claim.

What is claimed is:

I. In a camera having a housing and a film supply spool rotatablymounted therein; an improved film rewinding device which comprises:

an operation member rotatably mounted in said housing;

a shaft rotatable within said housing and engaging said supply spool tocause rotation thereof; and

means for selectively coupling said operation member and said shaft,said coupling means including a gear train interconnected to said shaft,a first wheel fixed to said operation member having a toothed portionengageable with said gear train, and a toothless portion, a second wheelarranged coaxially with and rotatable relative to said first wheel andhaving a toothed portion engageable with said gear train and a toothlessportion, and means for limiting the relative rotation between saidwheels to selectively locate said wheels at a disconnecting position inwhich both the toothless portions are opposed to said gear train, and ata connecting position in which at least one of said toothed portions isopposed to and in engagement with said gear train whereby upon rotationof said film spool in film advancement said toothless portions areopposed to said gear train to disconnect said operation member therefromand upon rotation of said operation member in film rewinding direction,at least one of said toothed portions engages said gear train tooperatively connect said operation member to said shaft.

2. A film rewinding device according to claim 1, wherein said limitationmeans comprises a pin provided on said first wheel and a limited slotprovided on said second wheel adapted to receive said pin.

3. A film rewinding device according to claim 1, wherein said gear traincomprises a toothed wheel fixed to said shaft and an intermediatetoothed wheel mounted to said camera housing for rocking movement andengageable with said wheel and said first and second wheels, and thefilm rewinding device further comprises a stopper for controlling theengaging position of said intermediate wheel relative to said first andsecond wheels, and an biasing member for urging said intermediate wheelto its engaging position.

4. A film rewinding device according to claim I. wherein said operatingmember extends outside of said camera housing for manual operation.

5. A film rewinding device according to claim 4, which further comprisesa shield member mounted between said operating member and said camerahousing for preventing a fluid from entering said camera housing byclose contact action of the deformation of the shield member.

# 1! i i i

1. In a camera having a housing and a film supply spool rotatablymounted therein; an improved film rewinding device which comprises: anoperation member rotatably mounted in said housing; a shaft rotatablewithin said housing and engaging said supply spool to cause rotationthereof; and means for selectively coupling said operation member andsaid shaft, said coupling means including a gear train interconnected tosaid shaft, a first wheel fixed to said operation member having atoothed portion engageable with said gear train, and a toothlessportion, a second wheel arranged coaxially with and rotatable relativeto said first wheel and having a toothed portion engageable with saidgear train and a toothless portion, and means for limiting the relativerotation between said wheels to selectively locate said wheels at adisconnecting position in which both the toothless portions are opposedto said gear train, and at a connecting position in which at least oneof said toothed portions is opposed to and in engagement with said geartrain whereby upon rotation of said film spool in film advancement saidtoothless portions are opposed to said gear train to disconnect saidoperation member therefrom and upon rotation of said operation member infilm rewinding direction, at least one of said toothed portions engagessaid gear train to operatively connect said operation member to saidshaft.
 2. A film rewinding device according to claim 1, wherein saidlimitation means comprises a pin provided on said first wheel and alimited slot provided on said second wheel adapted to receive said pin.3. A film rewinding device according to claim 1, wherein said gear traincomprises a toothed wheel fixed to said shaft and an intermediatetoothed wheel mounted to said camera housing for rocking movement andengageable with said wheel and said first and second wheels, and thefilm rewinding device further comprises a stopper for controlling theengaging position of said intermediate wheel relative to said first andsecond wheels, and an biasing member for urging said intermediate wheelto its engaging position.
 4. A film rewinding device according to claim1, wherein said operating member extends outside of said camera housingfor manual operation.
 5. A film rewinding device according to claim 4,which further comprises a shield member mounted between said operatingmember and said camera housing for preventing a fluid from entering saidcamera housing by close contact action of the deformation of the shieldmember.